February i8, 191 5] 



NATURE 



667 



fies its title, and stands entirely apart. The alarm- 

 ing" illustration with which it opens, representing^ 

 a statue of Louis Ag-assiz plung^ed head-downwards 

 in the ground, is not symbolical of the tendencies 

 of the text. The author traces the growth of geo- 

 logical philosophy without exulting over the im- 

 perfections of those who have gone before. The 

 hardy old pieces justificatives are quoted, but are 

 supplemented by observations of very recent 

 origin. On p. 141, for instance, Day and Shep- 

 herd's work on the volcanic gases of Hawaii is 

 cited in refutation of the critical thesis so en- 

 ticingly maintained by Brun ; but how many of our 

 current text-books have got so far as mentioning 

 Brun? He certainly never shook Tarr's faith in 

 the potency of steam as a volcanic agent ("College 

 Physiography," p. 444), and Prof. Gregory's re- 

 ferences are all the more welcome as recording a 

 leally memorable, if short-lived, controversy. 



The chapters on "How mountains are made," 

 with its review of the possible influence of radium, 

 and on "How mountains are upheld," with its 

 lucid exposition of isostasy, are good examples of 

 Prof. Gregory's method. The section devoted to 

 life-history, occupying nearly half the book, con- 

 tains no detailed description of stratified forma- 

 tions, but consists of essays on "The Origin of 

 Life," "The Interpretation of Fossils," "The 

 Evolution of Mammals," and so forth. Miss 

 Alice Woodward has contributed some spirited 

 original drawings of incidents in the life of fossil 

 vertebrates, and Hagenbeck's models at Hamburg 

 are also utilised. In these chapters the terrestrial 

 and fluviatile origin of the Old Red Sandstone con- 

 glomerates is well stated (p. 204) ; we are intro- 

 duced to Gigantosaurus of East Africa, the super- 

 dreadnought of land-animals (p. 259); and to the 

 beaked flints from the English Pliocene (p. 306), 

 for which the author is quite willing to accept a 

 human origin. 



On glacial matters he preserves considerable 

 caution ; here only his geology seems not quite of 

 to-day, though it is that of a very recent yester- 

 dav. To describe (p. 212) the evidence of Permian 

 glaciation as indicating that "the climate of parts 

 of the Southern Hemisphere was therefore colder 

 than it is at present," must be regarded as a very 

 moderate statement. In his memorable journeys 

 in Spitsbergen, Prof. Gregory (p. 227) was un- 

 fortunate in not coming across modern boulder- 

 clavs. The precise parallel between the material 

 left behind by the von Post glacier and that of 

 deposits in the British Isles would, for instance, 

 have reassured him. Too little seems made 

 of the fact that sheets of boulder-clay repre- 

 sent the unmeltable residue of glaciers that, in 

 their lower portions, consist half of ice and half 

 NO. 2364, VOL. 94] 



of stones. During the melting of such glaciers 

 there is no copious flow in the lower layers suffi- 

 cient to sweep aw-ay all the finer particles. The 

 loamy matter settles downwards in the interstices 

 of the abundant and striated stones. 



The fine series of photographs of Javan vol- 

 canoes is very welcome. So is the whole of this 

 stimulating volume. The author does not accept 

 (p. 81) the opinion of German writers as to the 

 origin of their own word feldspath ; but A. Brong- 

 niart attempted the same thing in 1807 in his 

 " Traite de Mineralogie " (p. 355) without success. 



{2) The handsome book by the late Prof. Tarr 

 and Mr. L. Martin is of the serious and detailed 

 type suggested by its title. It owes much to 

 the extensive and observant travels of Prof. 

 Tarr, and particularly to his work on glaciers and 

 recent uplifts in Alaska (pp. 214, 390, etc.). The 

 illustrations are numerous, and some of the dia- 

 grams would bear enlargement, those on river- 

 erosion, for instance, being not too clear (p. 557, 

 etc.). The view of Innsbruck on p. 525 represents 

 the snow of spring or autumn, but not "The Alps 

 rising above the snow line." The illustrations, 

 however, generally supplement in a valuable way 

 those of European text-books. The treatment of 

 the features due to stationan.- and shrinking ice- 

 sheets is especially interesting (ch. ix). The last 

 seven chapters, dealing with the atmosphere and 

 terrestrial magnetism, are due to the faithful and 

 experienced editor, Mr. L, Martin, who has 

 worked and travelled with Prof. Tarr. 



Grenville A. J. Cole. 



MA THEM A TIC A L TEXT-BOOKS. 



(i) Pendlebury's New Concrete Arithmetic. By 

 C. Pendlebury and H. Leather. First Year. 

 Pp. 57. Price 4J. Second Year. Pp. 54. Price 

 4d. Third Year. Pp. 57. Price 4/i. Fourth 

 Year. Pp. 56. Price 6d. Fifth Year. Pp. 71. 

 Price 6d. (London : G. Bell and Sons, Ltd. , 

 1914.) 



(2) A First Course in Mathematics for Techmcal 

 Students. By P. J. Haler and A. H. Stuart. 

 Pp. vi + 125. (London: University Tutorial 

 Press, Ltd., 191 4.) Price 15. 6d. 



(3) .4 Course of Geometry Theoretical and Practi- 

 cal: a Class-book for Secondary and Technical 

 Schools. By A. H. BeU. Pp. viii + 127. 

 (London : Rivingtons, 1914.) Price 2s. 6d. 



(4) .4 Treatise on Dynamics. By Dr. \V. H. 

 Besant. Revised and enlarged by X. S. Ram- 

 sey. Fifth edition. Pp. xv + 443. (London : 

 G. Bell and Sons, Ltd., 1914) Price 125. 



(5) Examples and Test Papers in Algebra. By 

 W. J. Walker. Parts ii. and iii. Pp. viii + 



